Effect of Urban Closed Circuit Television on Assault Injury and Violence Detection V Sivarajasingam, J P Shepherd, K Matthews

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ORIGINAL ARTICLE Effect of urban closed circuit television on assault injury and violence detection V Sivarajasingam, J P Shepherd, K Matthews ......

Injury Prevention 2003;9:312–316

Objective: To evaluate the effect of closed circuit television (CCTV) surveillance on levels of assault injury and violence detection. Design: Intervention versus control study design. Setting: Five town/cities with CCTV surveillance and five, matched control centres without CCTV surveillance in England. See end of article for Intervention: CCTV installation and surveillance. authors’ affiliations Methods: Assault related emergency department attendances and violent offences recorded by the police ...... in CCTV and control centres in the four years, 1995–99, two years before and two years after CCTV Correspondence to: installation, were compared. Dr Vaseekaran Results: Assault related emergency department attendances decreased in intervention centres (3% Sivarajasingam, Department of Oral decrease, ratio 0.96; 95% confidence interval (CI) 0.93 to 0.99) and increased in control centres (11% Surgery, Medicine and increase, ratio 1.11; 95% CI 1.08 to 1.14). Overall, changes in emergency department assault attendance Pathology, Violence in CCTV and control centres were significantly different (t test, p,0.05). Police recorded violence Research Group, University of Wales increased in CCTV (11% increase, ratio 1.16; 95% CI 1.08 to 1.24) and control centres (5% increase, ratio College of Medicine, 1.06; 95% CI 0.99 to 1.13). Overall, changes in police recording in CCTV and control centres were not Heath Park, Cardiff CF14 significantly different (t test, p.0.05). In CCTV centres, decreases in assault related emergency department 4XY, UK; attendances and increases in police violence detection were not uniform. [email protected] Conclusion: CCTV surveillance was associated with increased police detection of violence and reductions ...... in injury or severity of injury. CCTV centre variation deserves further study.

iolence is a major cause of physical and psychological potential assailants must be aware of the presence of factors injury, deformity, disability, and premature death. that increase the chances of detection,6 and many assailants/ Prevention of violence related morbidity and mortality protagonists, often through intoxication, are unlikely to be V 7 has become an important public health issue in many aware of the presence of CCTV surveillance. countries.1 In the past decade there has been a proliferation To test these hypotheses, it was necessary to study of closed circuit television (CCTV) in public and private numbers of violent offences and numbers of those injured settings, including town centres, with the United Kingdom in violence treated in emergency departments. Ideally, boasting the most extensive CCTV surveillance of public comparisons of offences and injuries in precise locations spaces in the world.2 This has resulted from initiatives by covered by CCTV surveillance versus those not covered by local and central government, funded in part by the European CCTV surveillance were necessary. However, the known Community, local authorities, and businesses. A goal of CCTV concentration of violence in a few urban centre streets with surveillance is the prevention of crime (that is, personal and large numbers of licensed premises provided justification for property) and disorder but there is little evidence of this comparing total emergency department assault related effect, except in relation to acquisitive crime like theft and car attendances with total violent offences.5 In England, emer- 3 crime. A recent systematic review on the crime prevention gency departments are situated either within or in very close effects of CCTV included 18 evaluations and concluded that proximity of town and city centres. Also, installation of public 4 CCTV reduces crime to a small degree. An important space CCTV is concentrated in urban centre entertainment unanswered question is whether CCTV is effective in areas where the night time economy is concentrated and preventing town/city centre violence. We carried out a study population dynamics are high. Therefore almost all persons to evaluate the effect of CCTV systems on violence detection sustaining assault injury requiring treatment within these and assault injury in town/city centres in England. centres would have attended the single emergency department serving the town/city and any effect on assault injury METHODS and violence detection after CCTV installation would be In this study, a focus of interest was the possible differential expected to become apparent. This proxy measure of public effect of CCTV on police and emergency department urban centre violence was also justified because other measures of violence, since police records reflect the detection categories of violence, such as domestic violence, workplace of offences whereas emergency department records reflect violence, and violence inside licensed premises would not be treatment. It is known that treatment for assault injuries is expected to be affected by public space CCTV. Furthermore, provided predominantly by emergency departments.5 It was the use of non-CCTV comparison centres would reduce the hypothesised that CCTV might increase police detection of contributions of these and other potential confounding assaults and that early detection of precursors to violence (for example, arguments) by CCTV might limit injury. This would be expected to decrease violence related emergency depart- ...... ment attendance. Importantly for a deterrent effect, however, Abbreviations: CCTV, closed circuit television; CI, confidence interval

www.injuryprevention.com Closed circuit television, violence, and injury 313

Table 1 Intervention and control centres

Intervention centres (CCTV installation date) Data collection period Control centres Data collection period

Ashford (May 1997) May 1995–April 1999 Derby May 1995–April 1999 Eastbourne (July 1997) July 1995–June 1999 Huntingdon May 1995–April 1999 Lincoln (March 1997) March 1995–Feb 1999 Poole May 1995–April 1999 Newport (July 1997) July 1995–June 1999 Chelmsford May 1995–April 1999 Peterborough (April 1997) April 1995–Mar 1999 Scarborough May 1995–April 1999

CCTV, closed circuit television. factors. Unfortunately, the extent of CCTV surveillance in were also collated locally by police personnel and disclosed England did not allow a randomised trial. without confidential information. Numbers of violence Five towns/cities (Ashford, Eastbourne, Lincoln, Newport related emergency department attendances and violent (Isle of Wight), and Peterborough) with street CCTV installed offences over a period of four years were compared: two between March and July 1997 were selected from a sample years before and two years after CCTV installation (table 1). frame (n = 56) of CCTV towns/cities in England, obtained In the five intervention town/cities, CCTV surveillance was from the National CCTV Users Group. This group comprised undertaken by the local council in four (Ashford, Lincoln, towns and cities with street CCTV installed for the purpose of Newport, and Peterborough) centres and by police in one reducing crime. CCTVs in all five centres were operational (Eastbourne). In the four council controlled CCTV systems 24 hours a day. Selection of control town/city centres was links with the police comprised a dedicated telephone line in more difficult as large and increasing numbers of towns and the CCTV control room and a video monitor at the police cities in England had CCTV cameras installed within their station. CCTV operators observed the areas covered and centres as part of crime reduction programmes. Five control information on assaults and precursors to assaults was towns/cities (Chelmsford, Poole, Derby, Scarborough, and relayed to police personnel. Any action taken based on the Huntingdon) without CCTV were selected randomly from the information relayed rested solely with the police. Action same geographical region and with approximately the same involved directing foot and/or vehicle patrols to the incident population but which were not included in the National site. CCTV Users Group list. The absence of CCTV was confirmed by telephone calls to local council and police. During this Data analysis selection process three towns/cities not included in the Scatter diagrams with quarterly moving averages were used National CCTV Users Group list were found to have CCTV to plot emergency department and police recorded violence installed within their centres and were excluded. Data were data for all 10 centres over the four year period. The Student’s available from all centres and all emergency departments t test was used to compare changes in violence before and categorised attendances according to cause of injury so that after CCTV installation. Injury and violent crime data for the all assault related attendances could be identified. First point first two years were compared with injury and violence data of patient contact was with triage personnel, before registra- for the last two years (table 2). Lack of co-terminosity tion by receptionists. It is usually at this stage that the reason between areas served by emergency departments and police for attendance (assault in this study) is entered into command units did not justify comparison of emergency emergency department computer records. Patients were then department and police data. referred to the emergency department medical officer and to specialists if required. The outcomes were discharge without RESULTS further review, discharge with review in an outpatient Overall, CCTV installation was associated with a significant department, or admission. For every new incident a new decrease in numbers of those reporting injury in assault at record was created. Emergency department recorded assault emergency departments (23%, ratio 0.96, 95% confidence data in this study were retrieved locally without individual interval (CI) 0.93 to 0.99) and was associated with a patient identifiers. Violent offences data relating to assault significant (11%, ratio 1.16; 95% CI 1.08 to 1.24) increase and wounding which occurred in city centre police beat areas in violent offences recorded by the police (table 2). In

Table 2 Emergency department and police recorded violence in CCTV and control towns

Emergency department Police

Before CCTV After CCTV Ratio 95% CI Significance Before CCTV After CCTV Ratio 95% CI Significance

CCTV centres Ashford 1050 1093 1.04 0.95 to 1.13 213 201 0.94 0.77 to 1.14 Eastbourne 1602 1479 0.92 0.86 to 0.99 Q 245 400 1.63 1.39 to 1.91 q Lincoln 3097 3283 1.06 1 to 1.11 q 412 457 1.10 0.97 to 1.26 Newport 1183 1077 0.91 0.83 to 0.98 Q 274 255 0.93 0.78 to 1.1 Peterborough 1262 991 0.78 0.72 to 0.85 Q 485 579 1.19 1.05 to 1.34 q Aggregate 8194 7923 0.96 0.93 to 0.99 Q 1629 1892 1.16 1.08 to 1.24 q Control centres Chelmsford 1761 2044 1.16 1.08 to 1.23 q 299 355 1.18 1.01 to 1.38 q Poole 1470 1388 0.94 0.87 to 1.01 352 328 0.93 0.80 to 1.08 Derby 4704 5093 1.08 1.04 to 1.12 q 867 928 1.07 0.97 to 1.17 Scarborough 1046 1242 1.18 1.09 to 1.28 q 169 200 1.18 0.96 to 1.45 Huntingdon 743 1050 1.41 1.28 to 1.55 q 83 69 0.83 0.60 to 1.14 Aggregate 9724 10817 1.11 1.08 to 1.14 q 1770 1880 1.06 0.99 to 1.13

q, Significant increase at the 5% level; Q, significant decrease at the 5% level; CCTV, closed circuit television; CI, confidence interval.

www.injuryprevention.com 314 Sivarajasingam, Shepherd, Matthews

Figure 1 Trends in recorded violence in Newport, Isle of Wight Figure 3 Trends in recorded violence in Ashford (intervention centre) (intervention centre) showing the three month moving averages for showing three month moving averages for emergency department injury emergency department injury and police violence records. Vertical line and police violence records. Vertical line indicates month of CCTV indicates month of CCTV installation. installation. contrast, in the control centres overall, there was a significant recorded by the police in the last two years (1997–99) increase in assault related emergency department attendance compared with the first two years (1995–97) of the study (11%, ratio 1.11; 95% CI 1.08 to 1.14) but no significant (table 2). In four control centres no significant change in change in violence recorded by the police (5%, ratio 1.06; 95% police recording was observed. CI 0.99 to 1.13). The change in assault attendance at emergency departments in CCTV towns was significantly Intervention centres different from change in emergency department attendance CCTV installation was associated with a significant reduction in control centres (3% decrease compared with 11% increase, in assault related emergency department attendance in t test, p,0.05). The change in police recorded violence in Newport, Peterborough, and Eastbourne (figs 1, 2, and 5) CCTV centres was not significantly different from police and a significant increase in Lincoln (fig 4). In contrast, there recorded violence in control centres (11% increase compared were significant increases in violence detected by the police in with 5% increase, t test, p.0.05). Changes in CCTV centres Peterborough and Eastbourne (figs 2 and 5) but no were not uniform (figs 1 to 5). significant decreases (table 2). There were differences in the pattern of reduction in violence related injury after CCTV Control centres installation. For example, in Newport, reduction in assault In four of five control centres (Chelmsford, Derby, related attendance appears to be gradual over the two year Huntingdon, and Scarborough) there were significantly more period after CCTV installation. In Peterborough reduction in assault related injury emergency department attendances in emergency department attendance appeared to take place the last two years (1997–99) compared with the first two only during the first year after CCTV installation and was years (1995–97) (table 2). Assault related emergency depart- followed by an increase in emergency department recorded ment attendances in Poole did not change significantly over attendance. the four year period (table 2). In one of five control centres There were also differences in the pattern of increase in (Chelmsford) there were significantly more violent offences violence recorded by police after CCTV installation. For example, in Eastbourne an increase was observed approximately six months before CCTV became operational and in Peterborough a gradual increase was observed after CCTV installation.

DISCUSSION The main findings in this study were that CCTV was associated with increased police detection of violence but reduced emergency department treatment. As most violence is known to be concentrated in relatively few streets within town and city centres,6 this study would have been expected to identify any clear changes in the incidence of violence and injury consequent upon CCTV installation. If there had been a significant deterrent effect as a result of CCTV installation then a decline in police detection of violence rather than the noted increase would have occurred. This study provides no evidence of a deterrent effect. A number of important methodological factors distinguish this study from previous evaluations of the effect of CCTV. Firstly, this study focused on both health services (emergency Figure 2 Trends in recorded violence in Peterborough (intervention centre) showing three month moving averages for emergency department) and police data. Secondly the study was carried department injury and police violence records. Vertical line indicates out over a four year period in contrast to previous studies in month of CCTV installation. which before and after periods were either too short—

www.injuryprevention.com Closed circuit television, violence, and injury 315

Figure 4 Trends in recorded violence in Lincoln (intervention centre) Figure 5 Trends in recorded violence in Eastbourne (intervention showing three month moving averages for emergency department injury centre) showing three month moving averages for emergency and police violence records. Vertical line indicates month of CCTV department injury and police violence records. Vertical line indicates installation. month of CCTV installation. typically, three months before and after installation—or even after the first year, perhaps through deteriorating CCTV of periods of unequal length.8 Thirdly, this study was ascertainment, communication of CCTV derived information concerned only with the effect of CCTV on violent crime to patrol police officers, or through inaction. In four of the and assault injury: in the majority of CCTV studies, different five control centres (Chelmsford, Derby, Huntingdon, and categories (violence, theft, public order) of crime have been Scarborough) there were significant increases in emergency grouped together concealing possible increases in some department assault attendances, with Poole showing no categories and decreases in others.9 Given the limited number significant change over the study period. There were of town and city centres without CCTV in England and Wales substantial individual centre differences, with significant at the time of study, close matching of CCTV and control increases in two centres (Eastbourne and Peterborough) and centres was not possible. However, the selection process no significant change in three centres (Ashford, Lincoln, and resulted in the best possible match of CCTV and five control Newport). There were no significant reductions in police centres. recorded violence in any of the control centres. Theoretically, CCTV may act via a variety of mechanisms on Previous injury research suggests a mechanism for the violent crime. Perpetrators may be detected, and removed; differential effect on emergency department and police CCTV may deter potential offenders who perceive an measures of violence observed in this study. In a prospective increased risk of detection; CCTV may direct security study of 539 adult victims of assault attending a major city personnel to locations where precursors to offending have centre emergency department it was found that, overall, been detected, which may head off their translation into severe injury was progressively more likely as the reported crime and/or reduce the severity of harm; CCTV could number of blows increased and that most assaults were symbolise efforts to take crime seriously, and the perception preceded by an argument/dispute.11 Increased surveillance by of those efforts may both energise law abiding citizens and/or means of CCTV and the opportunity for prompt police action deter crime. The presence of CCTV may induce people to take may therefore explain the apparently conflicting results of elementary security precautions, for fear that they will be this study: the benefit of CCTV might lie less in preventing shamed by being shown on CCTV.10 such offences (which it is argued will occur anyway because Overall, emergency department data suggested that CCTV of their impulsive nature and the role of alcohol), but more in surveillance significantly limited injury sustained in public facilitating a faster police response to arguments or assaults space violence in town/city centres which would otherwise in public spaces, which limits their duration and therefore have been sustained if CCTV had not been installed. In reduces the incidence and seriousness of injury. Overall, the contrast, CCTV installation was associated with increases in results of this study provide evidence which supports the police detection. This finding exemplifies the inappropriate- ness of measures of violence based only on police recording— which continue to be prominently and misleadingly pub- Key points lished. Differences in the pattern of decrease in violence related N Public space CCTV surveillance was associated with attendances in Newport and Peterborough emergency increased police detection of violence. departments suggest that there were local differences in N Public space CCTV surveillance was associated with police responses to CCTV surveillance. The rapid decline in reduction in numbers of people injured in assault who violence related injury in Peterborough during the first year were treated at emergency departments. after installation could reflect greater vigilance by CCTV N Impact of CCTV on police detection and assault injury operators in Peterborough or increased or accelerated police was not uniform across intervention towns and cities. responsiveness to incidents. This interpretation fits with a N significant increase in police recorded violence in Effectiveness of CCTV lies less in preventing assaults Peterborough over the same period. However, the rapid fall and their precursors, but more in preventing injury in violence related emergency department attendances in through increased police detection and intervention. Peterborough after CCTV installation was not maintained

www.injuryprevention.com 316 Sivarajasingam, Shepherd, Matthews utility of CCTV in terms of harm reduction and as a prompt to and Pathology, Violence Research Group, University of Wales College police action, but does not support its utility as a violence of Medicine, Cardiff, UK deterrent. K Matthews, Cardiff Business School, Cardiff, UK This study has demonstrated individual town/city centre differences in the effects of CCTV. Differences in the REFERENCES proportion of public space covered by cameras, lighting 1 Shepherd JP. Tackling violence. BMJ 1998;316:879. within the city centre, vigilance of CCTV operators, and police 2 Short E, Ditton J. Does closed circuit television prevent crime? CCTV Today responsiveness are some of the factors that may account for 1995;2:10–12. 3 Tilley N. Understanding car parks, crime and CCTV: evaluation lessons from these differences. Further multicentre studies in which local safer cities. Home Office police research group crime prevention unit series. authority and police scrutiny and responsiveness are studied Paper 42. London: Home Office, 1993. are an important priority in the identification of explanatory 4 Welsh BC, Farrington DP. Crime prevention effects of closed circuit television: a systematic review. London: Home Office Research Study 252, factors. This study provides evidence that emergency depart- 2002. ment data should be developed as a measure of community 5 Shepherd JP, Brickley MR. Alcohol intoxication, stressors and injury in urban violence related injury and of the effectiveness of CCTV and violence. Br J Criminol 1996;36:546–66. police services. It also highlights the disadvantages of 6 Von Hirsch A, Bottoms AE, Burney E, et al. Criminal deterrence and sentence severity: an analysis of recent research. Oxford: Hart Publishing, 1999. simplistic, uncontrolled research methodology in criminolo- 7 Shepherd JP. Emergency room research on links between alcohol and violent gical intervention studies and the serious shortcomings of injury. Addiction 1998;93:1261–2. police crime data as a measure of violence. 8 Brown B. CCTV in town centres: three case studies. Police Research Group Crime Detection and Prevention Series. Paper 68. London: Home Office, 1995. ACKNOWLEDGEMENTS 9 Ditton J, Short E. When open street CCTV appears to reduce crime: does it just We thank Robert Newcombe for statistical advice and emergency get displaced elsewhere? CCTV Today 1998;5:13–16. department and police managers for data sharing. 10 Armitage R, Smyth G, Pease K. Burnley CCTV evaluation. In: Painter K, Tilley N, eds. Surveillance of public spaces: CCTV, street lighting and crime ...... prevention. Vol 10. Crime prevention studies. Monsey, NY: Criminal Justice Press, 225–50. Authors’ affiliations 11 Shepherd JP, Shapland M, Pearce NX, et al. Pattern, severity and aetiology of V Sivarajasingam, J P Shepherd, Department of Oral Surgery, Medicine injuries in victims of assault. J R Soc Med 1990;83:75–9.

LACUNAE ......

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